Document handling is one of the important tasks performed by most computers. Documents can be created, edited, printed, stored and filed by computers via word processing and other types of applications running on the computer. In addition, computers can exchange documents via parallel and/or serial ports as well as over telephone lines via modems. A modem is an interface device coupled between a data terminal such as a computer and a telephone line. The modem permits the exchange of digital data between remote data terminals over the telephone line by providing an interface function between each terminal and the telephone network. The modem is typically plugged into a telephone jack connected to a telephone line and is positioned inside or adjacent to the associated data terminal. To support transmission of digital computer data to a remote data terminal, the modem transforms the digital data from the local data terminal into analog form necessary for telephone line transmission. On the receiving end, a second modem transforms received analog signals into digital data which is provided to its local data terminal. Faxmodems are special types of modems which permit computers to receive and transmit document data using facsimile protocols.
Oftentimes it is desirable to process a document which exists only in paper format. Such a document cannot readily be processed by the computer because it is not stored in a digital format on a medium compatible with the computer such as a floppy disk or tape. A scanner is a computer peripheral device which can read the document, convert it to a digital data format, and forward the digital data to the computer over an interface. The computer can then carry out normal document processing functions on the document as if the computer itself had created it. Facsimile machines have been used to serve the function of scanners where a computer has a faxmodem so that it can receive the facsimile data.